This simple, ingenious design keeps drones from breaking when they crash

FlexiQuad is a simple yet ingenious design that keeps drones from breaking when they crash. This drone features a hollow ring structure crafted from flexible materials, as opposed to the traditional quadcopter design that uses four stiff arms bolted to a central body. The rotors are placed on a ring with the batteries and electronics evenly distributed around the rim, and the middle of the ring is empty.

The ring's flexibility is its superpower, as it absorbs the force of impact and bounces back, keeping the drone airborne. The design is inspired by the wings of birds and insects, which bend in some directions but not others—a property called anisotropic stiffness. ETH Zürich researchers, Luca Girardi and Stefano Mintchev, developed the drone, which takes about five years to perfect.

The FlexiQuad can flex sideways, where the force of a collision will push, while staying rigid vertically to allow the propellers to lift the entire body without wobbling or sagging. The drone can flex up to 50 mph and accelerate at more than three times the force of gravity, making it as maneuverable as a regular drone. The design is four times more collision resilient than a regular drone and can fold itself thin enough to slip through an opening 70% as wide as its normal width.

Its flexibility allows for easy transport and the ability to carry payloads heavier than itself. The drone's inventors say it will be inexpensive to make, with a raw cost of less than $15, not counting motors, electronics, and batteries.